Method for fingerprint recognition and fingerprint recognition device

ABSTRACT

A method for fingerprint recognition and a fingerprint recognition device are provided. The method includes the following steps. A touch position of a touch panel is obtained as a fingerprint position. A fingerprint recognition operation is performed according to the fingerprint position. Whether the fingerprint recognition operation is successful is determined. In response to determining that the fingerprint recognition operation is not successful, at least one first position of the touch panel as an updated fingerprint position is generated according to the touch position of the touch panel, and the fingerprint recognition operation is performed according to the updated fingerprint position.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of U.S. provisionalapplication Ser. No. 62/944,319, filed on Dec. 5, 2019. The entirety ofthe above-mentioned patent application is hereby incorporated byreference herein and made a part of this specification.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a fingerprint recognition technique, and moreparticularly to a method for fingerprint recognition and a fingerprintrecognition device.

Description of Related Art

In fingerprint recognition techniques, a user first registers or enterstheir own registered fingerprint image or file in an electronic device,and when using the electronic device is needed, a finger is placed on afingerprint sensor for recognition. When the fingerprint recognition issuccessful, the electronic device using the fingerprint recognitiontechnique may be successfully unlocked for use by a user.

Moreover, when fingerprint recognition fails, there are twopossibilities: the first possibility is that this fingerprint is anunregistered fingerprint, and therefore the fingerprint recognition isbound to fail; the second possibility is that the fingerprint is aregistered fingerprint, but because the fingerprint texture is affectedby some factors (such as dry weather, finger injury, water droplet onthe fingerprint, etc.), the fingerprint recognition result is affected,such that fingerprint recognition fails. When the fingerprintrecognition fails, the electronic device often informs the user to lifttheir finger and press it on the fingerprint sensor again, thusresulting in repeated attempts to trying different pressing positionsuntil the recognition is successful. However, if the fingerprint imagecontains areas not readily recognized, the user needs to change thepressing position multiple times during fingerprint recognition,resulting in worse user somatosensory feedback on fingerprintrecognition.

SUMMARY OF THE INVENTION

The invention provides a method for fingerprint recognition and afingerprint recognition device that may perform fingerprint recognitionmultiple times without a user adjusting a pressing position of a fingerand without being aware to increase the accuracy of the fingerprintrecognition and improve the somatosensory feedback of the user forfingerprint recognition.

The method for fingerprint recognition of an embodiment of the inventionincludes the following steps: obtaining a touch position of a touchpanel as a fingerprint position; determining a fingerprint readout zoneaccording to the fingerprint position, and performing a fingerprintsensing operation according to the fingerprint readout zone to obtain afingerprint image to be determined corresponding to the fingerprintreadout zone; performing a fingerprint recognition operation accordingto the fingerprint image to be determined; generating at least one firstposition of the touch panel according to the touch position of the touchpanel and fingerprint matching information in response to determiningthat the fingerprint recognition operation is not successful; and,determining an updated fingerprint readout zone according to the atleast one first position, and performing the fingerprint sensingoperation according to the updated fingerprint readout zone.

The fingerprint recognition device of an embodiment of the inventionincludes a touch panel, a fingerprint sensor, a touch sensor, a hostcontroller, and a fingerprint readout device. The touch sensor iscoupled to the touch panel to sense a touch position of the touch panelas a fingerprint position. The host controller is coupled to the touchsensor. The fingerprint readout device is coupled to the fingerprintsensor and the host controller. The fingerprint readout devicedetermines a fingerprint readout zone according to the fingerprintposition and performs a fingerprint sensing operation according to thefingerprint readout zone, to obtain a fingerprint image to be determinedcorresponding to the fingerprint readout zone. The host controllerperforms a fingerprint recognition operation according to thefingerprint image to be determined. One of the host controller and thefingerprint readout device generates at least one first position of thetouch panel according to the touch position of the touch panel andfingerprint matching information in response to the host controllerdetermines that the fingerprint recognition operation is not successful.The fingerprint readout device determines an updated fingerprint readoutzone according to the at least one first position, and performs thefingerprint sensing operation according to the updated fingerprintreadout zone.

Based on the above, in the fingerprint recognition device and thecorresponding method of an embodiment of the invention, another positionas the updated fingerprint position adjacent to the touch position isautomatically generated according to the touch position provided by thetouch sensor when the first fingerprint recognition fails, and theupdated fingerprint readout zone is set using the updated fingerprintposition to perform fingerprint recognition again. Therefore, in thepresent embodiment, when the user does not adjust the pressing positionof the finger and the fingerprint recognition fails for the first time,fingerprint recognition is performed multiple times in different readoutzones, so that the accuracy of fingerprint recognition may still beincreased without having the user change the pressing position multipletimes, thus improving the user's somatosensory feedback on fingerprintrecognition.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a diagram of a fingerprint recognition device according to anembodiment of the invention.

FIG. 2 is a flowchart of a method for fingerprint recognition accordingto an embodiment of the invention.

FIG. 3 is a circuit diagram of the display panel, a fingerprint sensorthereof, and a fingerprint readout circuit in the controller in FIG. 1.

FIG. 4 is a diagram of a fingerprint recognition device according toanother embodiment of the invention.

FIG. 5 is a diagram of a first embodiment of generating a first positionof the touch panel in step S260 in FIG. 2.

FIG. 6 is a diagram of a second embodiment of generating a firstposition of the touch panel in step S260 in FIG. 2.

FIG. 7 is a diagram of a third embodiment of generating a first positionof the touch panel in step S260 in FIG. 2.

FIG. 8 is a diagram of a fourth embodiment of generating a firstposition of the touch panel in step S260 in FIG. 2.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a diagram of a fingerprint recognition device 100 according toan embodiment of the invention. The fingerprint recognition device 100may be applied to various electronic devices, such as a smart phone, atablet computer, a multimedia player, etc. The fingerprint recognitiondevice 100 mainly includes a touch panel 110, a touch sensor 120, and acontroller 130. In the present embodiment, the controller 130 mayinclude a host controller 132 and a fingerprint readout circuit 134. Thehost controller 132 may be a system core processing unit, an applicationprocessor in an electronic device, a central processor, etc. Thefingerprint readout circuit 134 of the present embodiment may be asingle fingerprint readout chip that is independently provided. In someembodiments, the touch sensor 120 and the fingerprint readout device inthe controller 130 may be integrated into a fingerprint, touch, anddisplay drive integrated (FTDI) chip.

The touch panel 110 may be a touch display panel, the touch panel 110includes a fingerprint sensor, and the fingerprint sensor includes afingerprint sensing pixel array. An optical fingerprint sensor may beembedded in the touch display panel, and a capacitive fingerprint sensormay be embedded in the touch display panel or arranged outside the touchpanel 110. The fingerprint sensing panel is combined with the touchdisplay panel, so that the fingerprint sensing area on the fingerprintsensing panel and the display area on the touch display panel areoverlapped with each other. The fingerprint sensor may be implemented bya fingerprint scanning circuit. Please refer to FIG. 3 and thecorresponding description for a detailed implementation example of thefingerprint sensor.

The touch sensor 120 is coupled to the control panel 110. In the presentembodiment, the touch sensor 120 senses the touch position of the touchpanel 110. When a finger of a user or a capacitive sensing element (suchas a stylus) touches the touch panel 110, that the finger positioninformation that the touch sensor 120 senses on the touch panel 110 isreported as a touch position in the form of coordinates, and the touchsensor 120 may send information of the touch position to the hostcontroller 132 in the controller 130 and then the host controller 132may send the touch position to the fingerprint readout circuit 134, orthe touch sensor 120 may not pass through the host controller 132 butdirectly transmit the information of the touch position to thefingerprint readout circuit 134 as the fingerprint position.

The fingerprint readout device 134 determines a fingerprint readout zoneaccording to the fingerprint position and performs a fingerprint sensingoperation according to the fingerprint readout zone to obtain afingerprint image to be determined corresponding to the fingerprintreadout zone, and the fingerprint readout device 134 transmits theobtained fingerprint image to be determined to the host controller 132,such that the host controller 132 performs a fingerprint recognitionoperation according to the fingerprint image to be determined, that is,determines the fingerprint image to be determined belongs to aregistered fingerprint image of a user. If the fingerprint recognitionoperation is successful, the electronic device using the fingerprintrecognition device 100 is unlocked and available for use by the user. Incontrast, if the fingerprint recognition operation is not successful, inthe present embodiment, the user is not immediately notified to changeto the pressing position on the touch panel 110 at this time, but therelated steps of the present embodiment are continued without the user'sawareness so as to perform fingerprint recognition multiple times, thusincreasing the accuracy of fingerprint recognition and improving theuser's somatosensory feedback on fingerprint recognition.

FIG. 2 is a flowchart of a method for fingerprint recognition accordingto an embodiment of the invention. The method for fingerprintrecognition in FIG. 2 may be implemented in the fingerprint recognitiondevice 100 in FIG. 1. Please refer to FIG. 1 and FIG. 2 at the sametime. In step S210 of FIG. 2, when a user touches or presses the touchpanel 110 with a finger or a capacitive sensing element (such as astylus), the touch sensor 120 senses multiple touched positions on thetouch panel 110 and determines a touch coordinate (that is, touchposition FP1) from them, and the touch coordinate usually corresponds tothe touched position with the maximum touch sensitivity. The hostcontroller 132 of the controller 130 obtains the touch position FP1 ofthe touch panel 110 from the touch sensor 120. The touch sensor 120 maysend information of the touch position to the host controller 132 in thecontroller 130 and then the host controller 132 may send the touchposition to the fingerprint readout circuit 134, or the touch sensor 120does not pass through the host controller 132 but directly transmits theinformation of the touch position to the fingerprint readout circuit 134as the fingerprint position.

In step S220, the host controller 132 of the controller 130 controls thefingerprint readout circuit 134 to perform a fingerprint sensingoperation according to the fingerprint position (i.e., the touchposition FP1). The steps of the fingerprint sensing operation describedin the present embodiment may be described as follows. First, thefingerprint readout circuit 134 sets a readout zone RZ1 located on thetouch panel 110 according to the fingerprint position FP1, wherein thefingerprint position FP1 is located in the readout zone RZ1. In thepresent embodiment, the fingerprint position FP1 is located at thecenter of gravity of the finger of the user, and the fingerprintposition FP1 is the center point of the readout zone RZ1. For example,if the size of the readout zone RZ1 in the present embodiment is 100*100fingerprint sensing pixels, and the coordinate information of thefingerprint position FP1 is (150, 150), then the fingerprint readoutcircuit 134 may determine the readout zone RZ1 is (100 to 200, 100 to200), that is, the coordinate information (150, 150) of the fingerprintposition FP1 is used as the center point, and the pixels are expanded by50 in the horizontal direction and the vertical direction to form the100*100 readout zone RZ1.

Secondly, the fingerprint readout circuit 134 obtains the fingerprintimage to be determined in the readout zone RZ1 of the touch panel 110via the fingerprint sensor of the touch panel 110. Then, the hostcontroller 132 performs the fingerprint recognition operation accordingto the fingerprint image to be determined. That is, the host controller132 determines whether the fingerprint image to be determined belongs toa registered fingerprint image of the user. If the host controller 132determines that the fingerprint image to be determined belongs to theregistered fingerprint image of the user, the fingerprint recognitionoperation is successful, if the host controller 132 determines that thefingerprint image to be determined is not the registered fingerprintimage of the user, then the fingerprint recognition operation failed.The registered fingerprint image is formed by the user registering orentering their own fingerprint information in advance in the fingerprintrecognition device 100.

In the present embodiment, the host controller 132 recognizes whetherthe fingerprint image to be determined obtained by scanning the readoutzones (for example, readout zones RZ1 and RZ2 in FIG. 1) by thefingerprint readout circuit 134 is the expected user identity, and thehost controller 132 does not have to recognize the complete fingerprintimage. The size setting of the readout zones is related to the number ofsignal processing channels (such as analog front-end circuits oranalog-to-digital conversion circuits) of the fingerprint readoutcircuit 134 that may simultaneously receive fingerprint sensing signals.If the host controller 132 must determine the success of the fingerprintrecognition operation based on the fingerprint image information of alarger area than the readout zone RZ1, the fingerprint readout circuit134 may be controlled to sequentially scan a plurality of readout zonesand integrate a plurality of fingerprint images corresponding to thereadout zones after scanning into a single fingerprint image andtransmit the single fingerprint image to the host controller 132.

In step S230, the host controller 132 determines whether the fingerprintrecognition operation is successful. If the host controller 132determines that the fingerprint recognition operation is successful,step S235 is performed after step S230, and the electronic device usingthe fingerprint recognition device 100 is unlocked and available for useby the user. In contrast, when the host controller 132 determines thatthe fingerprint recognition operation is not successful (that is,failed), the host controller 132 in the present embodiment firstdetermines whether the number of failed fingerprint recognitionoperations is excessive, thereby determining whether to continueperforming the fingerprint sensing operation and the fingerprintrecognition operation multiple times by adjusting the fingerprintposition (see the disclosure of step S260 and S220 in FIG. 2 below)without notifying the user.

In detail, when the fingerprint recognition operation is determined tobe not successful (i.e., failed) in step S230, step S240 is performedafter step S230, and the host controller 132 of the controller 130counts a number of failures. In step S250, the host controller 132 ofthe controller 130 determines whether the number of failures is greaterthan a preset predetermined value. When the number of failures is notgreater than the preset predetermined value, step S260 is performedafter step S250, and one of the host controller 132 and the fingerprintreadout device 134 generates at least one first position (e.g., aposition FP2) located on the touch panel 110 as the updated fingerprintposition according to the touch position FP1 of the touch panel 110 andfingerprint matching information, and the fingerprint readout device 134determines an updated fingerprint readout zone according the at leastone updated fingerprint position. Then, step S220 is performed afterstep S260, and the host controller 132 controls the fingerprint readoutdevice 134 to perform a fingerprint sensing operation according to theupdated fingerprint position (the first position FP2). For example, thefingerprint readout device 134 performs the fingerprint sensingoperation set on the readout zone RZ2 on the touch panel 110 (or, thereadout zone RZ2 of the fingerprint sensor) according to the updatedfingerprint position (the first position FP2), the fingerprint readoutdevice 134 obtain the fingerprint image to be determined (as the digitaldata) by fingerprint sensing pixels distributed in the readout zone RZ2,and the host controller 132 determines whether the fingerprintrecognition operation is successful by comparing the fingerprint imageto be determined with the registered fingerprint image of the user(e.g., step S230).

Therefore, in the case in which the user does not adjust the pressingposition of the finger and the first fingerprint recognition fails, inthe present embodiment, at least one first position (the updatedfingerprint position) FP2 are generated using the original fingerprintposition FP1, and different readout zones are obtained according to theat least one first positions FP2, so as to perform the fingerprintrecognition operation multiple times, so that the accuracy offingerprint recognition may still be increased without having the userchange the pressing position multiple times, thus improving the user'ssomatosensory feedback on fingerprint recognition. In other words, whenthe fingerprint recognition operation fails and the pressing position ofthe finger of the user is not changed, the host controller 132 controlsthe fingerprint readout device 134 to adjust the position of the readoutzone to be scanned, so as to probabilistically prevent the readout zonefrom containing fingerprint areas that are not readily recognized (e.g.,injured finger, broken fingerprint, water droplet on finger).

When the number of failures in step S250 is greater than the presetpredetermined value, the fingerprint recognition device 100 performs aplurality of fingerprint recognition operations according to a pluralityof updated fingerprint positions adjacent to the fingerprint positionFP1, but none of the fingerprint recognition operations is successful,and therefore at this point the fingerprint recognition should beregarded as a failure. At this time, step S255 is performed after stepS250, and the host controller 132 may present a warning signal via thesound effect of the display panel 110 or the electronic device, and thewarning signal is used to notify the user to indicate that thefingerprint recognition is not successful. Alternatively, the hostcontroller 132 may also present a notification signal via the soundeffect of the display panel 110 or the electronic device to notify theuser to change the pressing position of the finger of the user (forexample, the user is asked to lift the finger and press it somewhere inthe fingerprint sensing area on the display panel 110 again to changethe fingerprint position of the finger, and steps S210 to S260 arerepeated to perform fingerprint recognition again). In contrast, whensteps S220, S230, S240, S250, and S260 are performed again, the hostcontroller 132 does not present a notification signal to notify the userto change the pressing position of the finger of the user. In the aboveembodiments, the steps performed by the host controller 132 may beimplemented by hardware digital circuits or software programs in thehost controller 132.

The fingerprint sensor and the fingerprint readout circuit in the touchpanel 110 are described here. FIG. 3 is a circuit diagram of the displaypanel 110, a fingerprint sensor thereof, and the fingerprint readoutcircuit 134 in the controller 130 in FIG. 1. The fingerprint sensor 310in the touch panel 110 has a plurality of fingerprint sensing pixelcircuits 320. The fingerprint sensor 310 may be embedded in the displaypanel 110 or may be presented as an independent fingerprint sensingpanel. The fingerprint sensing panel and the display panel 110 arecombined with each other so that the fingerprint sensing area (that is,the area covered by the fingerprint sensor 310) on the fingerprintsensing panel and the display area on the display panel 110 areoverlapped with each other. The area covered by the fingerprint sensor310 is all or a portion of the display area on the display panel 110,and those applying the present embodiment may adjust the area covered bythe fingerprint sensor 310 according to their needs.

The fingerprint sensor 310 of the present embodiment includes X*Yfingerprint sensing circuits for forming a pixel array, and X and Y areboth positive integers.

A single fingerprint sensing circuit 320 in FIG. 3 is depicted as anomitted schematic in which the fingerprint sensing circuit 320 includesa transistor and a switch. If the fingerprint sensor is an opticalfingerprint sensor, the actual fingerprint sensing circuit includes aphotosensitive element, a storage capacitor, and multiple transistors toimplement operations such as resetting, exposing, and capturing imagesof fingerprint sensing pixels. FIG. 3 only shows a voltage follower(illustrated as a transistor in short) and the selection transistor(illustrated as a switch in short) in the fingerprint sensing circuit320. The fingerprint sensor captures images row by row, the fingerprintsensor pixels in the same column are connected to the same sensing line324, and the sensing voltage Sout is output to the fingerprint readoutdevice 134 through the same sensing line 324. The multiple sensing linesof the fingerprint sensor can be as shown in FIG. 3, the multiplesensing lines are grouped into the fingerprint readout device 134 atintervals, so that the position of the readout zone in the horizontaldirection may be flexibly set.

The fingerprint readout circuit 134 in FIG. 1 is located in a chip 330of FIG. 3. The chip 330 is the fingerprint readout device 134, the touchsensor 120 and a display driver integrated into a fingerprint, touch anddisplay driver integrated chip.

Here, the operations of the touch sensor 120, the host controller 132,and the fingerprint readout circuit 134 in FIG. 1 on each step in FIG. 2in different embodiments are described.

In some embodiments, in response to the host controller 132 determinesthat the fingerprint recognition operation is not successful, thefingerprint readout device 134 actively generates at least one firstposition FP2 of the touch panel 110 as the updated fingerprint position(step S260) according to the touch position FP1 of the touch panel 110and the finger matching information. In addition, when the hostcontroller 132 decides to proceed to step S260 and the subsequent stepS220 after step S240 and step S250, the fingerprint readout device 134actively performs the fingerprint sensing operation according to theupdated fingerprint position and is not controlled by the hostcontroller 132.

FIG. 4 is a diagram of a fingerprint recognition device 400 according toanother embodiment of the invention. The touch panel 110, the touchsensor 120, the host controller 132, and the fingerprint readout circuit134 in FIG. 4 are all the same as the corresponding elements in FIG. 4.The difference between FIG. 1 and FIG. 4 is that both the touch sensor120 and the fingerprint readout device 134 are used to control thedisplay panel 110, so in the present embodiment, the touch sensor 120and the fingerprint readout device 134 are integrated with each otherinto a fingerprint, touch, and display driver integrated (FTDI) chip410.

In some embodiments, the host controller 132 is an active controller,and the FTDI chip 410 is passively controlled by the host controller 132to implement corresponding functions. In detail, please refer to FIG. 2and FIG. 4 at the same time. In step S210, the touch sensor 120 in theFTDI chip 410 generates the touch position FP1 of the touch panel 110.The host controller 132 controls the FTDI chip 410 to perform afingerprint sensing operation according to the fingerprint position FP1and then the host controller 132 performs the fingerprint recognitionoperation (step S220), and the host controller 132 determines whetherthe fingerprint recognition operation is successful (step S230). Inresponse to the host controller 132 determines that the fingerprintrecognition operation is not successful, the host controller 132generates at least one first position FP2 of the touch panel 110 as theupdated fingerprint position according to the touch position FP1 of thetouch panel 110 and the finger position information (generated by thehost controller 132), and then the fingerprint readout circuit 134determines the updated fingerprint readout zone (step S260). Thefingerprint readout device 134 performs the fingerprint sensingoperation according to the updated fingerprint readout zone and the hostcontroller 132 performs the fingerprint recognition operation (stepS220).

In some embodiments, the host controller 132 and the FTDI chip 410 areboth active controllers. In particular, the FTDI chip 410 may activelyperform step S260. In detail, please refer to FIG. 2 and FIG. 4 at thesame time. In step S210, the touch sensor 120 in the FTDI chip 410generates the touch position FP1 of the touch panel 110. The hostcontroller 132 controls the FTDI chip 410 to perform a fingerprintsensing operation according to the fingerprint position FP1 and then thehost controller 132 performs the fingerprint recognition operation (stepS220), and the host controller 132 determines whether the fingerprintrecognition operation is successful (step S230). In response to the hostcontroller 132 determines that the fingerprint recognition operation isnot successful, the fingerprint readout device 134 in the FTDI chip 410actively generates at least one first position FP2 of the touch panel110 as the updated fingerprint position according to the touch positionFP1 of the touch panel 110 and the finger matching information(generated by the host controller 132), and then the fingerprint readoutcircuit 134 determines the updated fingerprint readout zone (step S260),and the FTDI chip 410 actively performs the fingerprint sensingoperation according to the updated fingerprint readout zone and the hostcontroller 132 performs the fingerprint recognition operation (stepS220).

Here, how to generate at least one first position of the touch panelaccording to the touch position of the touch panel in step S260 in FIG.2 is described, and various embodiments that may be implemented arelisted. FIG. 5 is a diagram of a first embodiment of generating a firstposition of the touch panel in step S260 in FIG. 2. As shown in FIG. 5,when the host controller 132 determines the fingerprint recognitionoperation is not successful and step S260 in FIG. 2 is to be performed,the host controller 132 divides the fingerprint image to be determinedobtained via the readout zone RZ1 into a plurality of image areas. Thecenter point of the fingerprint image to be determined in the presentembodiment is the fingerprint position FP1, and the fingerprint image tobe determined is evenly divided into four image areas 511 to 514. Inaddition, the host controller 132 compares each of the image areas 511to 514 with a corresponding image located in the registered fingerprintimage of the user to calculate a matching value for each image area, andthus each of the image areas 511 to 514 is scored, and the matchingvalue or the score value is regarded as the fingerprint matchinginformation. In other words, the host controller 132 calculates thematching value of each of the image areas 511 to 514 according to adegree of image difference between each of the image areas 511 to 514and a preset registered fingerprint image. When the image differencebetween the image areas 511 to 514 and the preset registered fingerprintimage is greater, the calculated matching value is smaller; when theimage difference between the image areas 511 to 514 and the presetregistered fingerprint image is smaller, the calculated matching valueis greater.

After the matching value of each of the image areas 511 to 514 iscalculated, because the matching value of the image area 513 has thelargest value compared to the other matching values, the host controller132 or the fingerprint readout circuit 134 determines one of the imageareas having the largest matching value (for example, the image area513) as the selected image area. Then, the host controller 132 or thefingerprint readout circuit 134 sets a position in the selected imagearea 513 (for example, a vertex in the image area 513 relative to thefingerprint position FP1) as the first position FP2 of the touch panel110 (the updated fingerprint position) and determines the updatedfingerprint readout zone. That is, the host controller 132 or thefingerprint readout circuit 134 moves the fingerprint position FP1 to afirst quadrant to generate the first position FP2, and sets the readoutzone RZ2 according to the first position FP2 as the updated fingerprintcoordinate and performs a fingerprint recognition operation. In thepresent embodiment, if the fingerprint recognition operation performedbased on the first position FP2 is still not successful, the originalfingerprint position FP1 in FIG. 5 may be replaced with the firstposition FP2 and the corresponding steps of generating the firstposition are repeated, so as to suitably expand the application mode ofthe present embodiment.

FIG. 6 is a diagram of a second embodiment of generating a firstposition of the touch panel in step S260 in FIG. 2. As shown in FIG. 6,when the host controller 132 determines the fingerprint recognitionoperation is not successful and step S260 in FIG. 2 is to be performed,the host controller 132 divides the fingerprint image to be determinedobtained via the readout zone RZ1 into a plurality of image areas (suchas 9 image areas 611 to 619). The host controller 132 compares each ofthe image areas 611 to 619 with a corresponding image located in theregistered fingerprint image of the user to calculate a matching valuefor each of the image areas 611 to 619, and thus each of the image areas611 to 619 is scored. If the matching values of the image areas 611,612, and 613 are greater than the other matching values, the hostcontroller 132 or the fingerprint readout circuit 134 moves thefingerprint position FP1 upward to generate the first position FP2, andsets the readout zone RZ2 according to the first position FP2 as theupdated fingerprint coordinate and performs a fingerprint recognitionoperation. In the present embodiment, if the fingerprint recognitionoperation performed based on the first position FP2 is still notsuccessful, the host controller 132 or the fingerprint readout circuit134 replaces the original fingerprint position FP1 in FIG. 6 with thefirst position FP2 and the corresponding steps of generating the firstposition are repeated, so as to suitably expand the application mode ofthe present embodiment.

FIG. 7 is a diagram of a third embodiment of generating a first positionof the touch panel in step S260 in FIG. 2. As shown in FIG. 7, when thehost controller 132 determines the fingerprint recognition operation isnot successful and step S260 in FIG. 2 is to be performed, the hostcontroller 132 randomly divides the fingerprint image to be determinedobtained via the readout zone RZ1 into a plurality of image areas (suchas 3 image areas 711 to 713). The host controller 132 compares each ofthe image areas 711 to 713 with a corresponding image located in theregistered fingerprint image of the user to calculate a matching valuefor each of the image areas 711 to 713, and thus each of the image areas711 to 713 is scored. If the matching value of the image area 713 isgreater than the other matching values, the host controller 132 or thefingerprint readout circuit 134 moves the fingerprint position FP1toward the center area of the image area 713 to generate the firstposition FP2 (that is, the center area of the image area 713 is set tothe first position FP2), and the first position FP2 is set as theupdated fingerprint position. The fingerprint readout circuit 134 mayset the readout zone RZ2 to perform the fingerprint recognitionoperation.

FIG. 8 is a diagram of a fourth embodiment of generating a firstposition of the touch panel in step S260 in FIG. 2. As shown in FIG. 8,when the controller 130 determines the fingerprint recognition operationis not successful and step S260 in FIG. 2 is to be performed, the hostcontroller 132 or the fingerprint readout circuit 134 randomly dividesthe fingerprint image to be determined obtained via the readout zone RZ1into a plurality of image areas (such as 3 image areas 811 to 813). Thehost controller 1320 compares each of the image areas 811 to 813 with acorresponding image located in the registered fingerprint image of theuser to calculate a matching value for each of the image areas 711 to713, and calculates the weight of each of the image areas according tothe matching value of each of the image areas 711 to 713. Then, the hostcontroller 132 or the fingerprint readout circuit 134 may calculate themotion vector according to the weight of each of the image areas 711 to713, the matching value of each of the image areas 711 to 713, and thedistance between the image areas 711 to 713 and the fingerprint positionFP1 of the touch panel 110, and the first position FP2 is set accordingto the motion vector and the fingerprint position FP1.

For example, in the case that the weight of the image area 811 isexpressed as w1, the vector between the center point of the image area811 and the fingerprint position FP1 is expressed as Va, the weight ofthe image area 812 is expressed as w2, the vector between the centerpoint of the image area 812 and the fingerprint position FP1 isexpressed as Vb, the weight of the image area 813 is expressed as w3,and the vector between the center point of the image area 813 and thefingerprint position FP1 is expressed as Vc. Therefore, the distance anddirection of a motion vector Vd needed for the fingerprint position FP1to generate the first position FP2 may be calculated using the followingequation (1):Vd=Va×w1+Vb×w2+Vc×w3  (1)

That is, in the present embodiment, the motion vector Vd from thefingerprint position FP1 to the first position FP2 is calculated usingthe image areas 811 to 813 and the corresponding weights w1 to w3 usinga vector method, thereby generating the corresponding first position,and the readout zone is reset according to the first position as anupdated fingerprint coordinate and a fingerprint recognition operationis performed.

Based on the above, in the fingerprint recognition device and thecorresponding method of an embodiment of the invention, another positionas the updated fingerprint position adjacent to the touch position isautomatically generated according to the touch position provided by thetouch sensor when the first fingerprint recognition fails, and theupdated fingerprint readout zone is set using the updated fingerprintposition to perform fingerprint recognition again. Therefore, in thepresent embodiment, when the user does not adjust the pressing positionof the finger and the fingerprint recognition fails for the first time,fingerprint recognition is performed multiple times based on differentreadout zones, so that the accuracy of fingerprint recognition may stillbe increased without the user changing the pressing position multipletimes, thus improving the user's somatosensory feedback on fingerprintrecognition.

What is claimed is:
 1. A fingerprint recognition device, comprising: atouch panel; a fingerprint sensor; a touch sensor coupled to the touchpanel to sense a touch position of the touch panel; a host controllercoupled to the touch sensor; and a fingerprint readout device coupled tothe fingerprint sensor and the host controller, wherein the fingerprintreadout device determines a fingerprint readout zone according to thefingerprint position and performs a fingerprint sensing operationaccording to the fingerprint readout zone, to obtain a fingerprint imageto be determined corresponding to the fingerprint readout zone; the hostcontroller performs a fingerprint recognition operation according to thefingerprint image to be determined; one of the host controller and thefingerprint readout device generates at least one first position of thetouch panel according to the touch position of the touch panel and afingerprint matching information in response to the host controllerdetermines that the fingerprint recognition operation is not successful;the fingerprint readout device determines an updated fingerprint readoutzone according to the at least one first position, and performs thefingerprint sensing operation according to the updated fingerprintreadout zone.
 2. The fingerprint recognition device of claim 1, whereinthe touch sensor and the fingerprint readout device are integrated intoa fingerprint, touch, and display driving integrated (FTDI) chip.
 3. Thefingerprint recognition device of claim 1, wherein the host controllerdetermines whether the fingerprint image to be determined belongs to aregistered fingerprint image of a user, to determine whether thefingerprint recognition operation is successful.
 4. The fingerprintrecognition device of claim 3, wherein the host controller divides thefingerprint image to be determined into a plurality of image areas inresponse to the host controller determines that the fingerprintrecognition operation is not successful, wherein a center point of thefingerprint image to be determined is the fingerprint position, the hostcontroller compares each of the image areas with a corresponding imagelocated in a registered fingerprint image of the user to calculate amatching value for each of the image areas as the fingerprint matchinginformation, and one of the host controller and the fingerprint readoutdevice generates the at least one first position of the touch panelaccording to the image area and the matching value corresponding to eachof the image areas.
 5. The fingerprint recognition device of claim 4,wherein one of the host controller and the fingerprint readout devicedetermines one of the image areas having a maximum matching value as aselected image area, and sets a position in the selected image area asthe at least one first position of the touch panel.
 6. The fingerprintrecognition device of claim 4, wherein one of the host controller andthe fingerprint readout device calculates a weight of each of the imageareas according to the matching value of each of the image areas,calculates a motion vector according to the weight of each of the imageareas, the matching value of each of the image areas, and a distancebetween each of the image areas and the fingerprint position of thetouch panel, and sets the at least one first position of the touch panelaccording to the motion vector and the fingerprint position of the touchpanel.
 7. The fingerprint recognition device of claim 4, wherein thehost controller counts a number of failures when the fingerprintrecognition operation is determined to not be successful, and determineswhether the number of failures is greater than a predetermined value,the host controller presents a warning signal to notify the user thatthe fingerprint recognition operation is not successful in response todetermining that the number of failures is greater than thepredetermined value, or presents a notification signal to notify theuser to change a pressing position of a finger of the user.
 8. Thefingerprint recognition device of claim 7, wherein in response to thehost controller determines that the number of failures is not greaterthan the predetermined value, the fingerprint readout device performsthe fingerprint sensing operation according to the updated fingerprintreadout zone to obtain a second fingerprint image to be determinedcorresponding to the fingerprint readout zone, and the host controllerperforms the fingerprint identification operation according to thesecond fingerprint image to be determined.
 9. The fingerprintrecognition device of claim 1, wherein the fingerprint sensor isembedded in the touch panel.
 10. The fingerprint recognition device ofclaim 1, wherein the fingerprint sensor is arranged outside the touchpanel.
 11. A method for fingerprint recognition, comprising: obtaining atouch position of a touch panel as a fingerprint position; determining afingerprint readout zone according to the fingerprint position, andperforming a fingerprint sensing operation according to the fingerprintreadout zone to obtain a fingerprint image to be determinedcorresponding to the fingerprint readout zone; performing a fingerprintrecognition operation according to the fingerprint image to bedetermined; generating at least one first position of the touch panelaccording to the touch position of the touch panel and a fingerprintmatching information in response to determining that the fingerprintrecognition operation is not successful; and determining an updatedfingerprint readout zone according to the at least one first position,and performing the fingerprint sensing operation according to theupdated fingerprint readout zone.
 12. The method for fingerprintrecognition of claim 11, wherein the step of performing the fingerprintrecognition operation according to the fingerprint image to bedetermined comprises: determining whether the fingerprint image to bedetermined belongs to a registered fingerprint image of a user, todetermine whether the fingerprint recognition operation is successful.13. The method for fingerprint recognition of claim 11, wherein the stepof generating the at least one first position of the touch panelaccording to the touch position of the touch panel and the fingerprintmatching information comprises: dividing the fingerprint image to bedetermined into a plurality of image areas in response to determiningthat the fingerprint recognition operation is not successful, wherein acenter point of the fingerprint image to be determined is thefingerprint position; comparing each of the image areas with acorresponding image located in a registered fingerprint image of theuser to calculate a matching value for each of the image areas as thefingerprint matching information; and generating the at least one firstposition of the touch panel according to the image area and the matchingvalue corresponding to each of the image areas.
 14. The method forfingerprint recognition of claim 13, wherein the step of generating theat least one first position of the touch panel according to the imagearea and the matching value corresponding to each of the image areascomprises: determining one of the image areas having a maximum matchingvalue as a selected image area; and setting a position in the selectedimage area as the at least one first position of the touch panel. 15.The method for fingerprint recognition of claim 13, wherein the step ofgenerating the at least one first position of the touch panel accordingto the image area and the matching value corresponding to each of theimage areas comprises: calculating a weight of each of the image areasaccording to the matching value of each of the image areas; calculatinga motion vector according to the weight of each of the image areas, thematching value of each of the image areas, and a distance between eachof the image areas and the fingerprint position of the touch panel; andsetting the at least one first position of the touch panel according tothe motion vector and the fingerprint position of the touch panel. 16.The method for fingerprint recognition of claim 11, further comprising:counting a number of failures when the fingerprint recognition operationis determined to not be successful; determining whether the number offailures is greater than a predetermined value; and presenting a warningsignal to notify the user that the fingerprint recognition operation isnot successful in response to determining that the number of failures isgreater than the predetermined value, or presenting a notificationsignal to notify the user to change a pressing position of a finger ofthe user.
 17. The method for fingerprint recognition of claim 16,further comprising: in response to determining that the number offailures is not greater than the predetermined value, performing thefingerprint sensing operation according to the updated fingerprintreadout zone to obtain a second fingerprint image to be determinedcorresponding to the fingerprint readout zone, and performing thefingerprint identification operation according to the second fingerprintimage to be determined.